188.8.131.52 Fuel sampling fitting. A fuel sampling fitting shall be installed in a readily
accessible location, in the piping and not in any pipe fitting, downstream of the filter/separator
and upstream of the hose reel. The fitting shall be an Aeroquip part number AE96920E or equal.
The fitting shall be of anodized aluminum or stainless steel, complete with valve core, probe,
wire retaining rope and 7/16-14UNC-2A plug. The fitting shall mate and properly function with
Aeroquip part number AE96924E.
3.8.7 Contamination (fuel quality) monitor. A contamination monitor, meeting the
requirements of MIL-M-81380, shall be furnished and installed downstream of the
filter/separator. The monitor shall contain a built-in surge suppressor that will provide maximum
protection to the filter/separator in the event of a pressure surge in the system. One set of
monitor elements shall be provided. The monitor shall shut down fuel delivery when excessive
contaminant levels are reached in the fuel. The monitor shall be provided with a differential
pressure gage. The monitor differential pressure gage is not required if the contamination
monitor is incorporated into the filter/separator. The contamination monitor shall be certified by
the component manufacturer to be of adequate capacity for the maximum flow rates and
pressures possible for the pump and piping system furnished on the vehicle.
3.8.8 Meter. A positive displacement reversible meter with a maximum rating of not less
than 200 gpm shall be housed in the pumping system compartment. The meter shall be capable
of momentary overspeeding to 125 percent of maximum rated capacity without mechanical
damage or impairment of accuracy. The meter shall be designed for not less than 75 psig
working pressure and 125 psig hydrostatic test pressure. The meter shall have an accuracy in
accordance with the requirements of the National Bureau of Standards Handbook 44. The meter
shall be capable of being adjusted while under pressure without leakage or loss of the product.
The adjustment sensitivity shall be sufficiently fine to permit calibration changes in conformance
to the accuracy requirements set forth above and shall be capable of an adjustment range so that
the meter will be suitable for aviation gasoline, JP-4, JP-5 and JP-8 fuel, and adjustment shall be
accomplished without the use of external change gears. A vertical meter counter shall have a
seven figure totalizer and a four or five figure setback indicating full gallons. The numerals in
the setback shall be coated with light reflecting material. All components of the meter in contact
with the fuel shall be fabricated from aluminum material. Stainless steel may be used in
conjunction with aluminum for moving components of the meter having metal-to-metal contact.
3.8.9 Product flow control system. The control system shall automatically provide the
pressure control and flow relief functions to accomplish the performance requirements specified
in 3.8.4. The control system shall prevent pump speed surges, pressure surges, and any other
type of pumping system instability. The system shall automatically regulate to the required flow
conditions, as determined by the overwing nozzle and the aircraft fuel system ahead of the